[Inliner] Merge the attributes of the caller and callee functions

This patch turns off the fast-math optimization attribute on the caller
if the callee's fast-math attribute is not turned on.

For example,

- before inlining
 caller: "less-precise-fpmad"="true"
 callee: "less-precise-fpmad"="false"

- after inlining
 caller: "less-precise-fpmad"="false"

Alternatively, it's possible to block inlining if the caller's and
callee's attributes don't match. If this approach is preferable to the
one in this patch, we can discuss post-commit.

rdar://problem/19836465

Differential Revision: http://reviews.llvm.org/D7802

llvm-svn: 257575

2 files changed, 89 insertions, 0 deletions

diff --git a/llvm/include/llvm/IR/Attributes.td b/llvm/include/llvm/IR/Attributes.td
index 797cd55427b..30249bbd8fa 100644
--- a/llvm/include/llvm/IR/Attributes.td
+++ b/llvm/include/llvm/IR/Attributes.td
@@ -189,4 +189,9 @@ class MergeRule<string F> {
   string MergeFunc = F;
 }
 
+def : MergeRule<"setAND<LessPreciseFPMADAttr>">;
+def : MergeRule<"setAND<NoInfsFPMathAttr>">;
+def : MergeRule<"setAND<NoNansFPMathAttr>">;
+def : MergeRule<"setAND<UnsafeFPMathAttr>">;
+def : MergeRule<"setOR<NoImplicitFloatAttr>">;
 def : MergeRule<"adjustCallerSSPLevel">;
diff --git a/llvm/test/Transforms/Inline/attributes.ll b/llvm/test/Transforms/Inline/attributes.ll
index a97e6a60de7..0458fa23f79 100644
--- a/llvm/test/Transforms/Inline/attributes.ll
+++ b/llvm/test/Transforms/Inline/attributes.ll
@@ -160,3 +160,87 @@ define i32 @test_target_features1(i32 %i) "target-features"="+sse4.2" {
 ; CHECK-NEXT: @test_target_features_callee1
 ; CHECK-NEXT: ret i32
 }
+
+define i32 @less-precise-fpmad_callee0(i32 %i) "less-precise-fpmad"="false" {
+  ret i32 %i
+; CHECK: @less-precise-fpmad_callee0(i32 %i) [[FPMAD_FALSE:#[0-9]+]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @less-precise-fpmad_callee1(i32 %i) "less-precise-fpmad"="true" {
+  ret i32 %i
+; CHECK: @less-precise-fpmad_callee1(i32 %i) [[FPMAD_TRUE:#[0-9]+]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_less-precise-fpmad0(i32 %i) "less-precise-fpmad"="false" {
+  %1 = call i32 @less-precise-fpmad_callee0(i32 %i)
+  ret i32 %1
+; CHECK: @test_less-precise-fpmad0(i32 %i) [[FPMAD_FALSE]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_less-precise-fpmad1(i32 %i) "less-precise-fpmad"="false" {
+  %1 = call i32 @less-precise-fpmad_callee1(i32 %i)
+  ret i32 %1
+; CHECK: @test_less-precise-fpmad1(i32 %i) [[FPMAD_FALSE]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_less-precise-fpmad2(i32 %i) "less-precise-fpmad"="true" {
+  %1 = call i32 @less-precise-fpmad_callee0(i32 %i)
+  ret i32 %1
+; CHECK: @test_less-precise-fpmad2(i32 %i) [[FPMAD_FALSE]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_less-precise-fpmad3(i32 %i) "less-precise-fpmad"="true" {
+  %1 = call i32 @less-precise-fpmad_callee1(i32 %i)
+  ret i32 %1
+; CHECK: @test_less-precise-fpmad3(i32 %i) [[FPMAD_TRUE]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @no-implicit-float_callee0(i32 %i) {
+  ret i32 %i
+; CHECK: @no-implicit-float_callee0(i32 %i) {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @no-implicit-float_callee1(i32 %i) noimplicitfloat {
+  ret i32 %i
+; CHECK: @no-implicit-float_callee1(i32 %i) [[NOIMPLICITFLOAT:#[0-9]+]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_no-implicit-float0(i32 %i) {
+  %1 = call i32 @no-implicit-float_callee0(i32 %i)
+  ret i32 %1
+; CHECK: @test_no-implicit-float0(i32 %i) {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_no-implicit-float1(i32 %i) {
+  %1 = call i32 @no-implicit-float_callee1(i32 %i)
+  ret i32 %1
+; CHECK: @test_no-implicit-float1(i32 %i) [[NOIMPLICITFLOAT]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_no-implicit-float2(i32 %i) noimplicitfloat {
+  %1 = call i32 @no-implicit-float_callee0(i32 %i)
+  ret i32 %1
+; CHECK: @test_no-implicit-float2(i32 %i) [[NOIMPLICITFLOAT]] {
+; CHECK-NEXT: ret i32
+}
+
+define i32 @test_no-implicit-float3(i32 %i) noimplicitfloat {
+  %1 = call i32 @no-implicit-float_callee1(i32 %i)
+  ret i32 %1
+; CHECK: @test_no-implicit-float3(i32 %i) [[NOIMPLICITFLOAT]] {
+; CHECK-NEXT: ret i32
+}
+
+; CHECK: attributes [[FPMAD_FALSE]] = { "less-precise-fpmad"="false" }
+; CHECK: attributes [[FPMAD_TRUE]] = { "less-precise-fpmad"="true" }
+; CHECK: attributes [[NOIMPLICITFLOAT]] = { noimplicitfloat }